As a kind of close-range wireless communication, there is known wireless communication by NFC (near-field communication), which uses a carrier frequency of 13.56 MHz. On the other hand, there have been proposed technologies that utilize a coil used for NFC communication to achieve non-contact power feeding by magnetic field resonance.
In non-contact power feeding by magnetic field resonance, a transmission-side resonance circuit including a transmission-side coil is arranged in a power feeding appliance (power transmission device), and a reception-side resonance circuit including a reception-side coil is arranged in an electronic appliance as a power reception appliance (power reception device), with the resonance frequencies of the respective resonance circuits set at a common reference frequency. When, with the power reception appliance (power reception device) arranged on the power feeding stage of the power feeding appliance (power transmission device), an alternating current is passed in the transmission-side coil, an alternating magnetic field at the reference frequency is generated in the transmission-side coil. This alternating magnetic field propagates to the reception-side resonance circuit that resonates at the reference frequency, causing an alternating current to pass in the reception-side coil. Thus, electric power is transferred from the transmission-side resonance circuit including the transmission-side coil to the reception-side resonance circuit including the reception-side coil.